Lake Turkana , Kenya -LRB- CNN -RRB- -- Richard Leakey has spent a lifetime exploring Kenya 's Turkana Basin searching for the origins of man .

Each layer of sediment , says the paleoanthropologist and founder of the Turkana Basin Institute , helps to tell the narrative of human evolution .

`` You get the whole story of life represented going back from the present right back to the beginnings of an ape that has two legs as opposed to four , '' Leakey said .

`` So the whole story of humanity you can actually trace to the Turkana Basin . ''

But Leakey says these ancient hills tell another story , a history of climactic changes that gave rise to some species and led to the extinction of others .

With climate change , he says , this history could be repeated .

`` The future of humanity is not going to be in the sediments , it is going to be in our minds and our thinking and unfortunately what we find here is that evidence , '' Leakey said .

`` What we find here that is scientifically provable , immutable facts does n't necessarily get absorbed for the moment by the political class who simply do n't want to know the ugly truth that the world is a mess . ''

On the shores of Lake Turkana -- the largest desert lake in the world -- they do n't need to know the science of climate change .

For more than 1,000 years , fishermen have been bringing in their catch , but , in less than a generation , they have witnessed disturbing changes .

`` When I was young this lake was full , says Lazarao Maraka , a local fisherman .

`` The water just keeps going down . We used to get big fish every day , now they are tiny . ''

Maraka has reason to worry . Sometimes it is hard to see the effects of climate change , but not at Lake Turkana .

Global human impact on Earth

Thirty years ago the area was covered with water . Now , it is just sand and gravel . And scientists believe that in just a few decades it will be reduced to a couple of puddles .

Upriver dam projects could further hasten the retreat , a potential catastrophe for the entire region that depends on the lake for food and economic survival .

`` I think the prospect of many of these half million people living around the lake today of having to relocate to cities and to slums and to abandon their culture , abandon their ancestral land , become paupers in their own land , I think it is very real , '' Leakey says .

`` I think the way of life is gone ... I have no doubt about that at all . I think if you came back here or my grandchildren came back in 50 years we would n't recognize what we are talking about today . ''

Leakey 's Turkana Basin Institute is trying to understand how climate change is affecting the Turkana .

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Sometimes the best thing to do is listen . The Turkana say the rains are less frequent and the droughts come more often .

The unpredictable weather and vanishing pasture has decimated their herds .

Climate change does affect the Turkana people , says Ikal Angelei from the Turkana Basin Institute .

`` With the increase of drought it has made the communities unable to adapt to the changes , because it happens so often , '' Angelei said .

Leakey says that anyone skeptical about climate change should visit the Turkana Basin .

`` Coming to a place like this , I think you actually show people what happens . These are real issues that you can see and feel and almost touch that may make people understand that we are on the edge of a precipice and we are going over , '' he said .

`` We have accelerated a process and it is based on the belief that somehow we can maintain control . I think our carbon dioxide emissions are out of control . ''

Even with the changes around Lake Turkana , fishermen like Lazaro Maraka still try to eke out a living the only way they know how .

He worries what will be left for his son Eroo if the lake continues to recede .

`` If there is no lake or no fish , then the people will not survive around this lake . This lake is the Turkana 's life , '' Maraka says .

This place has helped unlock humanity 's past . Today , it could also be providing a window on its future .

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Conservationist Richard Leakey has been working in Kenya 's Turkana Basin for years

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Leakey says fishermen have seen evidence of climate change in the water as levels recede

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Potentially catastrophic as entire region is dependent on the lake for food and economic survival